Modular exoskeleton structure that provides force assistance to the user

ABSTRACT

A modular exoskeleton structure provides force assistance to a user. The structure includes a base module including a lumbar belt capable of surrounding the waist of the user, a battery and a control unit attached to the lumber belt, a first attachment part attached to the belt and capable of cooperating with a second complementary attachment part of a hip module to attach the hip module to the base module by snapping the second attachment part into the first attachment part, and a third attachment part attached to the belt and capable of cooperating with a complementary fourth attachment part of a back module for attaching the back module to the base module.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.16/065,604, filed Jun. 22, 2018, which is a National stage ofInternational Application No. PCT/EP2016/082597 filed on Dec. 23, 2016,which claims priority benefit from FR1563348 filed on Dec. 24, 2015, thecontents of each of which are herein incorporated by reference in theirentireties.

FIELD OF THE INVENTION

The invention relates to a modular exoskeleton structure that providesforce assistance to a user.

PRIOR ART

Exoskeletons that provide force assistance are mechanical structureswhich duplicate the structure of the human skeleton and which allow animprovement in the physical capacities of the human body.

There exist different exoskeletons that provide force assistance, ofwhich the shape and the structure depend on the tasks to be accomplishedby the user.

Generally, each exoskeleton is designed to assist the user foraccomplishing one very specific task.

For this reason, each exoskeleton is the subject of a specific designand development, and is generally not compatible to be used with anotherexoskeleton.

SUMMARY OF THE INVENTION

One aim of the invention is to propose an exoskeleton structure whichcan be adapted to different uses, and which can be supplied withelectrical energy without significantly impacting the metabolicoperation of the body of the user.

This aim is achieved within the scope of the present invention thanks toa modular exoskeleton structure that provides force assistance to auser, comprising:

-   -   a base module comprising a lumbar belt capable of surrounding        the waist of the user, a first battery and a control unit        attached to the lumbar belt,    -   a back module capable of being attached to the back of the user,        the back module comprising a second battery,    -   a first attachment part attached to the belt and capable of        cooperating with a second complementary attachment part of a hip        module to attach the hip module to the base module by snapping        the second attachment part into the first attachment part,    -   a third attachment part attached to the belt, and    -   a fourth complementary attachment part attached to the back        module,

wherein the third attachment part is capable of cooperating with thecomplementary fourth attachment part for attaching the back module tothe base module, the third attachment part and the fourth attachmentpart comprising a socket and a plug capable of being plugged into thesocket to electrically connect the second battery to the control unitwhen the fourth attachment part cooperates with the third attachmentpart.

Thanks to the attachment parts, a hip module and/or a back module can beattached rapidly and reversibly to the base module.

Moreover, other modules can be attached to the base module, such as asecond hip module so as to assist both lower limbs of the user, or abackpack support module for example.

The proposed structure also allows the creation, based on a set ofpre-existing modules, of different assemblies depending on the desireduses, or the completion of an assembly to adapt it to a new use.

Moreover, the structure can be used according to at least two possibleconfigurations.

According to one possible configuration, the back module is not attachedto the base module. In this configuration (without the back module), thefirst battery is sufficient to supply the actuators of the structure,particularly the actuators of the hip module when they are attached tothe base module.

According to another configuration, the back module is attached to thebase module. In this configuration, the addition of the back moduleincreases the consumption of electrical energy of the structure. Thesecond battery therefore allows the completion of the energycontribution supplied by the first battery.

As the first battery is attached to the lumbar belt, it is located nearthe center of mass of the user. This makes it possible to obtain adistribution of the masses of the structure around the body of the userwhich has little impact on the metabolic operation of the body (theenergy cost for the body is minimal).

Moreover, the first battery can have reduced bulk, which avoids inparticular impeding the natural sway of the arms of the user whenwalking.

The second battery, for its part, is not positioned on the base modulewith the first battery, but rather on the back module. This allowsavoiding an increase in volume of the base module which would have theeffect of impeding the natural sway of the arms of the user whenwalking.

In fact, when the volume disposed around the waist constrains thenatural sway of the arms, it then becomes more advantageous to disposethe mass of the second battery on the back module; given the positiveimpact of the sway of the arms on the energy of the center of mass.

Thus, the disposition of the first battery in the base module and thesecond battery in the back module leads to a distribution of masses ofthe batteries which minimizes the impact of the masses on the metabolicoperation of the body.

The proposed modular structure can also have the following features:

-   -   the structure also comprises at least one hip module capable of        being attached to a thigh of the user, each hip module        comprising a hip actuator, the hip actuator comprising a stator        and a rotor capable of being driven in rotation with respect to        the stator to drive in rotation the hip module with respect to        the base module during a flexure or extension movement of the        hip, the second attachment part being attached to the stator of        the actuator,    -   the first attachment part and the second attachment part form a        bayonet type attachment device in which one of either the first        part or of the second part comprises a radial pin, and the other        of the first part and the second part comprises a curved slot in        which the radial pin can slide, the slot being curved in such a        manner that the sliding of the pin in the slot from an entrance        of the slot to an end of the slot requires a combined        translation and rotation movement of the second part with        respect to the first part, the translation being accomplished        successively in a first direction, then in a second direction        opposite to the first direction,    -   the attachment device also comprises an elastic return element        capable of urging the second part in the second direction so as        to hold the second part snapped into the first part,    -   when the elastic return element urges the second part in the        second direction, the elastic return element tends to separate        the second part from the first part,    -   the hip module comprises a femoral portion capable of being        attached to the thigh of the user, the structure also comprising        at least one knee module comprising a tibial portion capable of        being attached to the calf of the user, and a knee joint capable        of connecting the femoral portion to the tibial portion by        allowing a rotation of the tibial portion with respect to the        femoral portion during a flexure and extension movement of the        knee,    -   the knee module comprises a connecting bar capable of being        inserted in a femoral segment of the femoral portion to attach        the knee module to the hip module,    -   the connecting bar is capable of sliding inside the femoral        segment of the hip module to allow adjustment of the distance        between the knee joint and the hip joint,    -   the structure also comprises at least one foot module capable of        being attached to the foot of the user, the foot module        comprising a connecting bar capable of being inserted in a        tibial segment of the tibial portion to attach the foot module        to the knee module,    -   the first part and the second part each comprise electrical        contacts capable of electrically connecting the first battery        and the control unit to the actuator when the second part is        snapped into the first part,    -   the structure comprises at least one elbow module capable of        being attached to an arm of the user,    -   the structure also comprises a shoulder module capable of        connecting the elbow module to the back module.

The invention also relates to a back module for an exoskeletonstructure, comprising a segment of spinal column designed to extendalong a spinal column of a user, the spinal column segment comprising aplurality of vertebral elements, stacked on one another, and a flexibleconnecting element connecting the vertebral elements to one another, thespinal column segment having a stable equilibrium position in which theflexible connecting element retains the vertebral elements supportedagainst one another and the flexible connecting element being elastic sothat, during a movement of the back of the user, the flexible connectingelement allows a displacement of the vertebral elements with respect toone another, while still exerting a return force tending to return thespinal column segment to the stable equilibrium position.

Such a back module allows the upper body of a user to be assisted insupporting loads, while conferring a greater freedom of movement.

The spinal column segment being formed from a plurality of vertebralelements supported against one another, it allows transmission of avertical load exerted on the back module and accommodation of themovements of the upper body of the user. In fact, the flexible elementallows a certain degree of freedom of the vertebral elements withrespect to one another, which confers a certain freedom of movement ofthe spinal column.

Moreover, the number of vertebral elements can be adjusted depending onthe size of the user, which allows the exoskeleton structure to beeasily adapted to the morphology of the user.

The module can also show the following characteristics:

-   -   the flexible connecting element exerts a compression force on        the vertebral elements so as to maintain the elements of the        vertebral elements in support against one another in the stable        equilibrium position,    -   the flexible connecting element extends inside the spinal column        segment through each of the vertebral elements, the flexible        connecting element being held under tension so as to exert a        compression force on the vertebral elements,    -   each vertebral element has a recess and a protrusion, each        protrusion being capable of being received in a recess of        another vertebral element situated immediately above or below in        the stack,    -   each vertebral element is connected to a following vertebral        element by a connection allowing a flexural and/or radial        rotation and/or lateral inclination movement of the back of the        user,    -   each vertebral element has an arched shape, with a concavity        oriented toward the lower part of the spinal column when the        spinal column segment extends along the spinal column of the        user,    -   the module also comprises one or more electrical transmission or        data transmission cable(s) extending inside the spinal column        segment through each of the vertebral elements, for connecting a        battery and/or actuators and/or sensors to a control module of        the exoskeleton structure, or for connecting two control modules        of the exoskeleton structure,    -   the electrical transmission or data cable(s) have a length        greater than a length of the spinal column segment, so that they        allow a deformation of the spinal column segment without        undergoing stretching,    -   the module comprises a connecting device comprising an        attachment part attached to a lower end of the spinal column        segment, the attachment part being capable of being attached to        a complementary attachment part attached to a lumbar belt of a        base module of the exoskeleton structure to attach the back        module to the base module.

The invention also relates to an exoskeleton structure that providesforce assistance to a user, comprising:

-   -   a base module comprising a lumbar belt capable of surrounding        the waist of the user, and an attachment part attached to the        belt, and    -   a back module as previously defined, comprising an attachment        part attached to a lower end of the spinal column segment, the        attachment part of the back module being capable of being        attached to the attachment part of the belt for attaching the        back module to the base module, so that a weight applied to the        spinal column element is transferred to the base module.

In one embodiment of the invention, the base module comprises a controlunit and a battery attached to the belt, and the back module comprisesand additional battery and/or actuators, and the attachment parts eachcomprise electrical contacts capable of electrically connecting thebattery and the control unit of the base module to the battery and/orthe actuators of the back module when the attachment part of the backmodule is attached to the attachment part of the base module.

PRESENTATION OF THE DRAWINGS

Other features and advantages will also be revealed by the descriptionthat follows, which is purely illustrative and not limiting and must beread with reference to the appended figures, among which:

FIG. 1 shows schematically, in front view, a user equipped with anexoskeleton structure conforming to a possible embodiment of theinvention,

FIGS. 2 and 3 show schematically, in back view and in profile view, theuser equipped with the exoskeleton structure in conformity with a firstpossible configuration of the invention,

FIGS. 4 and 5 show schematically, in back view and in profile view, theuser equipped with the exoskeleton structure in conformity with a secondpossible configuration of the invention,

FIGS. 6 and 7 show schematically, in back view and in profile view, theuser equipped with the exoskeleton structure, in conformity with a thirdpossible configuration of the invention,

FIGS. 8A and 8B show schematically a hip joint connecting a hip moduleto the base module,

FIG. 9 shows schematically an attachment device for attaching the hipmodule to the base module,

FIGS. 10A and 10B show schematically the attachment device in theunlocked configuration and in the locked configuration respectively,

FIG. 11 shows schematically lower modules of the exoskeleton structure,

FIGS. 12A to 12E show schematically a shoe equipped with a foot module,during different phases of walking of the user,

FIG. 13 shows schematically, in enlarged view, upper modules of theexoskeleton structure,

FIG. 14 shows schematically a spinal column segment forming part of theback module,

FIG. 15 shows schematically a vertebral element of the spinal columnsegment,

FIGS. 16 to 18 show schematically a shoulder module,

FIG. 19 shows schematically an attachment device for attaching theshoulder module to the elbow module,

FIGS. 20 and 21 show schematically a backpack support module,

FIG. 22 shows schematically an attachment device for attaching thebackpack support module to each hip module.

DETAILED DESCRIPTION OF ONE EMBODIMENT Modular Structure

In FIGS. 1 to 7, the exoskeleton structure shown comprises a base module1, a back module 2, two shoulder modules 3, two elbow modules 4, two hipmodules 5, two knee modules 6, two foot modules 7 and a backpack supportmodule 14.

The exoskeleton structure illustrated in these figures can be used indifferent configurations, so as to obtain different exoskeletons adaptedto different uses.

In a first configuration illustrated in FIGS. 1 to 3, the exoskeleton isformed by assembling the base module 1, the back module 2, the twoshoulder modules 3, the two elbow modules 4, the two hip modules 5, thetwo knee modules 6 and the two foot modules 7.

In a second configuration illustrated in FIGS. 4 and 5, the exoskeletonis formed by assembling only the base module 1, the back module 2, thetwo shoulder modules 3 and the two elbow modules 4.

In a third configuration illustrated in FIGS. 6 and 7, the exoskeletonis formed by assembling only the base module 1, the two hip modules 5,the two knee modules 6, the two foot modules 7 and the backpack supportmodule 14.

The three examples of configurations illustrated in these figures areobtained based on three different assemblies of the modular exoskeletonstructure. However, other configurations would of course be practicable.In these different configurations, the exoskeleton is formed from one ormore modules assembled together.

As illustrated in FIGS. 1 to 3, the base module 1 comprises a lumbarbelt 11 capable of surrounding the lower trunk of the user. The lumbarbelt 11 is disposed around the waist of the user, supported on the hipsof the user. The base module 1 also comprises a first battery 12allowing the different actuators of the structure to be supplied withelectrical energy, and a control unit 13 programmed to control thedifferent actuators. The first battery 12 and the control unit 13 areattached to the lumbar belt 11.

The back module 2 is adapted to be attached to the upper body of theuser above the base module 1, along the back of the user.

The elbow modules 4 are adapted to be attached to the arms of the user,respectively to the right arm and to the left arm.

Each shoulder module 5 is adapted to connect the back module 2 to arespective elbow module 4.

The back module 2, the shoulder modules 3 and the elbow modules 4 forman assembly of upper modules which have the function of assisting theuser with all the forces that he produces with his upper body, forexample when he carries out repetitive work with his upper body.

The hip modules 5 are adapted to be attached to the thighs of the user,respectively to the right thigh and to the left thigh of the user.

The knee modules 6 are adapted to be attached to the calves of the user,respectively to the calf of the right leg and to the calf of the leftleg of the user.

The foot modules 7 are adapted to be attached to the feet of the user,respectively to the right foot and to the left foot.

The hip modules 5, the knee modules 6 and the foot modules 7 form anassembly of lower modules which have as their function to assist theuser in the forces that he produces with his lower body, particularlywhen walking or when he carries or moves loads.

It will be noted that the hip modules 5 are symmetrical to one another.The hip modules 5 therefore comprise portions that are identical orsimilar.

Likewise, the knee modules 6 are symmetrical to one another and compriseidentical or similar portions.

The same is true of the foot modules 7, of the shoulder modules 3 and ofthe elbow modules 4.

Hip Module

As illustrated in FIGS. 1 to 3, each hip module 5 comprises a femoralportion 51 capable of being attached to the thigh of the user, and a hipjoint 52.

The femoral portion 51 comprises a femoral segment 511 designed toextend along the thigh of the user and attachment straps 512 capable ofsurrounding the thigh of the user to attach the femoral segment 511 tothe thigh.

Each hip module 5 is connected to the base module 1 through a respectivehip joint 52. More precisely, the hip joint 52 allows the femoralportion 51 of the hip module 5 to be connected to the belt 11 of thebase module 1.

Hip Joint

As illustrated in FIGS. 8A and 8B, the hip joint 52 comprises a hipactuator 521 allowing assistance to the user during flexure or extensionmovement of the hip of the user. The actuator 521 comprises a stator 522and a rotor 523 capable of being driven in rotation with respect to thestator 522 when the stator 522 is supplied with electrical energy todrive in rotation the hip module 5 with respect to the base module 1during a flexure or extension movement of the hip.

The hip joint 52 also comprises an elastic return element 524 arrangedto exert an elastic return force which assists the rotor 523 when theuser stands up from a seated or squatting position. The elastic returnelement 524 can comprise a preloaded spring disposed between the stator522 and the rotor 523, in a guide groove 525 provided between the stator522 and the rotor 523.

More precisely, the elastic return element 524 is arranged so that:

-   -   in a first angular range α₁ of movement of the rotor 523 with        respect to the stator 522, corresponding to an angular range in        which the rotor 523 is located when the user walks or runs (FIG.        8A), the elastic return element 524 does not exert any return        force on the rotor 523, and    -   in a second angular range α₂ of movement of the rotor 523 with        respect to the stator 522, corresponding to an angular range in        which the rotor 523 is located when the user sits or squats        (FIG. 8B), the elastic return element 524 exerts a return force        on the rotor 523.

To this end, the hip joint 52 comprises a tappet 526 mounted fixedly onthe rotor 523, the tappet 526 being capable of loading the elasticelement 525 in compression only when the rotor 523 is located in thesecond angular range α₂.

In this second range, the return force exerted by the elastic element524 tends to oppose a rotation of the rotor 523 with respect to thestator 522 in a first direction of rotation (arrow A) and to assist arotation of the rotor 523 with respect to the stator 522 in a seconddirection of rotation (arrow B), opposite to the first direction ofrotation.

The first direction of rotation (arrow A) is the direction of rotationof the rotor 523 with respect to the stator 522 when the user bends thethigh with respect to the upper body (when the user sits or squats).

The second direction of rotation (arrow B) is the direction of the rotor523 with respect to the stator 522 when the user extends the thigh withrespect to the upper body (when the user rises after having sat orsquatted).

In other words, when the rotor 523 is located in the second angularrange α₂, the elastic return element 524 exerts on the rotor 523 areturn force which tends to oppose a rotation of the hip module 5 withrespect to the base module 1 during a flexure movement of the hip andassist a rotation of the hip module 5 with respect to the base module 1during an extension movement of the hip.

The first angular range α₁ corresponds to a flexure or extensionmovement of the hip comprised for example between +60 degrees and −15degrees with respect to a frontal plane PF of the user.

The second angular range α₂ corresponds to a flexure or an extensionmovement of the hip greater than +90 degrees with respect to the frontalplane PF of the user.

Thus, in the first angular range α₁ of movement of the rotor of theactuator, the user benefits from active assistance through the actuator521, which in the second angular range α₂ of movement of the rotor ofthe actuator, the user benefits totally or as a supplement from passiveassistance through the elastic return element 524.

In this manner, the power delivered by the actuator 521 is limited inthe second angular range of movement.

The elastic element 524 can be supported against an abutment allowingthe spring to be kept pre-loaded. The position of the abutment withrespect to the stator can be adjustable, by means of screws for example,so as to be able to modify the angular ranges defined above.

Device for Attaching the Hip Module to the Base Module

The exoskeleton structure also comprises an attachment device 8 allowingthe hip module 5 to be attached to the base module 1.

FIGS. 9, 10A and 10B show schematically the attachment device 8. In theembodiment illustrated in these figures, the attachment device 8 is aso-called “bayonet type” attachment device. The attachment device 8 iscapable of passing from an unlocked configuration (illustrated in FIG.10A) in which the hip module 5 is detached from the base module 1, to alocked configuration (illustrated in FIG. 10B) in which the hip module 5is attached to the base module 1.

The attachment device 8 comprises a first part 81 mounted fixedly on thebase module 1 and a second part 82 mounted fixedly on the hip module 5.More precisely, the first part 81 is attached to the belt 11. The secondpart 82 is attached to the stator 522 of the actuator 521.

The second part 82 is capable of being snapped into the first part 81,so as to allow the reversible attachment of the hip module 5 to the basemodule 1.

The first part 81 comprises a body 811 having an insertion opening 812,and having an internal guide surface 813, with a cylinder-of-revolutionshape. The body 811 has a free edge 814 with a circular shape delimitingthe insertion opening 812. The first part 81 comprises two slots 815formed in the body 812 at diametrically opposite positions. Each slot815 extends from the free edge 814 of the first part 81 and has an end816. Moreover, each slot 815 has a U (or hairpin) shape and comprisestwo straight portions 817, 819 and a curved portion 818. The firststraight portion 817 extends from the free edge from the entrance to theslot 815 to the curved portion 818, in a direction parallel to the axisX of the internal guide surface 813. The curved portion 818 extends fromthe first straight portion 817 to the second straight portion 819,forming a bend. The second straight portion 819 extends from the curvedportion to the end 816. The portions thus delimit a boss 831 in the body811 of the first part 81.

The second part 82 comprises a body 821 having an external guide surface823 with a cylinder-of-revolution shape. The second part 82 is capableof being inserted into the first part 81 through the opening 812. Theinsertion of the second part 82 into the first part 81 is guided by thecylindrical surfaces 813 and 823 in contact with one another. The secondpart 82 comprises two radial pins 825 situated in diametrically oppositepositions, and protruding from the external surface 823. The radial pins825 are capable of being engaged in the slots 815 of the first part 81when the second part 82 is inserted into the first part 81.

The first part 81 is capable of being inserted into the second part 82in a first direction (arrow C) parallel to the axis X, corresponding toan insertion direction.

The attachment device 8 also comprises an elastic return element 83, inthe form of a spring, capable of loading the second part 82 in a seconddirection (arrow D), opposite to the first direction. The elasticelement 83 thus tends to oppose the insertion of the second part 82 intothe first part 81.

In the unlocked position (FIG. 10A), the second part 82 is disengagedfrom the first part 81.

In the locked configuration (FIG. 10B), the second part 82 is engaged inthe first part 81.

The locking of the attachment device 8 is accomplished by inserting thesecond part 82 into the first part 81 through the insertion opening 812.During this insertion, each pin 825 is introduced into a respective slot815.

Then the second part 82 is moved with respect to the first part 81 so asto cause each pin 825 to slide in the slot 815 in which it is received.Due to the shape of the slot 815, the sliding of the pin 825 from theentrance of the slot 815 to the end 816 of the slot 815 necessitates acombined movement of translation, parallel to the axis X, and rotationaround the axis X, of the second part 82 with respect to the first part81. The second part 82 is first translated with respect to the firstpart 81 in the first direction (insertion direction) counter to thereturn force exerted by the elastic element 83. Then the second part 82is translated in the second direction, opposite to the first direction,while undergoing rotation with respect to the first part 81 around theaxis X.

Once the pin 825 is positioned at the end 816 of the slot 815, thesecond part 82 is blocked in rotation with respect to the first part 81by the boss 831. Moreover, the elastic element 83 loads the second part82 in the second direction, which has the effect of retaining the pin825 in abutment against the end 816 of the slot 815. The elastic element83 and the boss 831 block the pin 825 in the slot 815 and preventdisengagement of the pin 815 from the slot 825.

In this manner, the second part 82 is held snapped into the first part81.

The un-snapping of the second part 82 is obtained by carrying out thereverse operation, that is by causing each pin 815 to slide along thereverse path from the end 816 of the slot 815 to the entrance of theslot 815. The sliding of the pion 815 from the end 816 of the slot 815to the entrance of the slot 815 again necessitates a combinedtranslation and rotation movement of the second part 82 with respect tothe first part 81. The second part 82 is first translated with respectto the first part 81 in the first direction (insertion direction)counter to the return force exerted by the elastic element 83 whileundergoing reverse rotation with respect to the first part 81. Then thesecond part 82 is translated with respect to the first part 81 in thesecond direction.

Moreover, the first part 81 and the second part 82 each compriseelectrical contacts capable of electrically connecting the first battery12 and the control unit 13 of the base module 1 to the actuator when thesecond part 82 is in the locked configuration in the first part 81.

Knee Module

As illustrated in FIG. 3, each knee module 6 comprises a connecting bar61, a knee joint 62 and a tibial portion 63 capable of being attached tothe calf of the user.

The connecting bar 61 is capable of sliding inside the femoral segment511 of the hip module 5, so as to attach the knee module 6 to the hipmodule 5, while allowing adjustment of the distance between the hipjoint 52 and the knee joint 62. A set screw allows the immobilization ofthe connecting bar 61 with respect to the femoral segment 511.

The tibial portion 63 comprises a tibial segment 631 designed to extendalong the calf of the user and attachment straps 632 capable ofsurrounding the shaft of the user to attach the segment 631 to the calf.

Once the knee module 6 is attached to the hip module 5, the tibialportion 51 is connected to the femoral portion 51 through the knee joint62. The knee joint 62 allows a rotation of the tibial portion 63 withrespect to the femoral portion 51 in a plane parallel to the sagittalplant of the user (corresponding to a flexure or extension of the kneeof the user).

The knee joint 62 can comprise an actuator allowing assistance to theuser during flexure or extension movement of the knee.

The actuator of the knee joint 62 can be identical to the actuator 521of the hip joint illustrated in FIGS. 8A and 8B. In particular, theactuator can comprise a stator, a rotor capable of being driven inrotation with respect to the stator to drive in rotation the knee modulewith respect to the hip module during a flexure or extension movement ofthe knee, and an elastic return element arranged to exert an elasticreturn force which assists the actuator when the user rises from aseated or squatting position. The elastic return element can comprise apre-loaded spring disposed between the stator and the rotor, in a guidegroove provided between the stator and the rotor.

However, in the case of a knee joint actuator, the angular ranges aredifferent. The first angular range α₁ corresponds to a flexure orextension movement of the knee comprised for example between +15 degreesand −60 degrees with respect to a frontal plane PF of the user. Thesecond angular range α₂ corresponds to a flexure or extension movementof the knee less than −60 degrees with respect to the frontal plane PFof the user.

The adjustment of the angular ranges can be obtained by modifying theposition of the abutment to which the spring is applied, with respect tothe stator.

Foot Module

As illustrated in FIG. 3, the foot module 7 is attached to the kneemodule 6.

The foot module 7 comprises a connecting bar 71, an ankle joint 72 and afoot portion 73 capable of being attached to the foot of the user.

The connecting bar 71 is capable of sliding inside the tibial segment631 of the knee module 6 so as to attach the foot module 7 to the kneemodule 6, while allowing adjustment of the distance between the kneejoint 62 and the ankle joint 72. A set screw allows immobilizing theconnecting bar 71 with respect to the tibial segment 631.

As illustrated in FIG. 11, the foot portion 73 comprises a first segment731, a first support plate 732, a second segment 733, a third segment734 and a second support plate 735.

The ankle joint 72 allows rotation of the foot module 7 with respect tothe knee module 6 during a flexure or extension movement, during apronation or supination movement and during an eversion or inversionmovement of the ankle of the user.

The ankle joint 72 comprises a first frame 721, a second frame 722capable of turning with respect to the first frame 721 during a rotationmovement of the foot of the user with respect to the calf, and anelastic element 723 disposed between the frames 721 and 722.

The first frame 721 is mounted fixedly on the connecting bar 71 of thefoot module 7 and the second frame 722 is mounted fixedly on the firstsegment 731 of the foot portion 73.

The elastic element 723 comprises a ring formed from an elastomericmaterial, pre-compressed between the first frame 721 and the secondframe 722. The elastic element 723 is capable of exerting a return forcetending to oppose the relative rotation of the second frame 722 withrespect to the first frame 721.

The first segment 731 connects the ankle joint 72 to the first supportplate 732. More precisely, the first segment 731 has a first endattached to the second frame 722 and a second end attached to the firstsupport plate 732.

The second segment 733 and the third segment 734 connect the firstsupport plate 732 to the second support plate 735 while forming an anglebetween them.

The second support plate 735 can have, on its lower surface designed tobe in contact with the ground, an anti-skid coating, made for example ofgrooved rubber.

In FIGS. 12A to 12D, the foot module 7 is used with a boot 9, of the“ranger” or “combat boot” type for example. The boot 9 is designed tosupport a load applied on top of the boot 9 which can go up to 40kilograms. The boot 9 can also comprise a shell protecting the front ofthe foot and/or reinforcing elements made of metal.

As illustrated in FIG. 12A, the first support plate 732 is designed tosupport the top of the boot 9 of the user.

The second support plate 735 is designed to be supported on the ground Swhen the user is standing on the ground. The second support plate 735 isarranged so that it is disposed below the sole 91 of the boot 9 of theuser, in a recess 92 formed in the sole between the heel 93 and theforefoot 94.

The first segment 731 and the second segment 733 form a V-shaped spring.The spring is capable of being compressed when the sole 91 of the boot 9is in contact with the ground (segments 731 and 733 move closertogether) and to be expanded when the sole 91 of the boot 9 is not incontact with the ground S (segments 731 and 733 move away from eachother).

The second segment 733 and the third segment 734 are connected to oneanother by an angle situated below the ankle joint 72. More precisely,the vertical axis V passing through the center of rotation of the anklejoint 72 intersects the two segments 733 and 734, when the user is inthe standing position. This position of the segments 733 and 734 withrespect to the ankle joint 72 allows the creation of a downwarddeformation of the foot portion 73, and therefore ensures that the footportion 73 tends to press on the front of the boot 9, and not to raisethe front of the boot.

FIGS. 12A to 12E illustrate different phases of the walking cycle of theuser.

In FIG. 12A, the sole 91 of the boot 9 is in contact with the ground S.During this phase, the second support plate 735 is in contact with theground S. The spring formed by the segments 731 and 733 is compressed sothat the weight exerted on the foot module 7 is transferred to theground S via the second support plate 735.

In FIG. 12B, the heel 93 of the boot 9 detaches from the ground S.During this phase, the spring formed by the segments 731 and 733expands. As it expands, the spring exerts on the foot module 7 an upwardreturn force F which assists the user in lifting the foot.

In FIG. 12C, only the front 94 of the sole 91 of the boot 9 is incontact with the ground S. The spring formed by the segments 731 and 733is expanded. The weight exerted on the foot module 7 is then transferredto the boot 9 via the first support plate 732. As long as the boot 9 isin contact with the ground, the weight is transferred to the ground viathe boot 9.

In FIG. 12D, once the foot has been lifted from the ground S, the weightis exerted mainly on the other foot module 7 of the exoskeletonstructure.

In FIG. 12E, the user again places the heel 93 on the ground S. Duringthis phase, the second support plate 735 is again in contact with theground S, which has the effect of compressing the spring formed by thesegments 731 and 733. The spring formed by the segments 731 and 733 iscompressed until the weight exerted on the foot module is transferred tothe ground S via the second support plate 735.

The foot module 7 allows transferring the load which is exerted on theexoskeleton to the ground S: when walking, the load is transferred tothe ground successively via the second support plate 735, then via thefirst support plate 732 and the boot 9 of the user.

The foot module 7 allows adaptation to boots currently in use by themilitary, without necessitating modification of the boot. The footmodule 7 can be used with a standard boot and does not requiremodification or adaptation of the boot.

The foot module 7 also allows the load carried by the user to betransferred to the ground, including during walking phases, and this forany type of terrain.

Back Module

FIG. 13 shows schematically, in enlarged view, the back module 2.

The back module 2 comprises a spinal column segment 21, a backrest 22and straps 23 allowing the backrest 22 to be attached to the back of theuser.

The spinal column segment 21 extends along the spinal column of the userwhen the back module 2 is attached to the back of the user. Moreprecisely, the spinal column segment 21 extends between the belt 11 ofthe base module 1 and the backrest 22.

The backrest 22 comprises a casing 221 and a second battery 222 housedin the casing 221.

Each shoulder module 3 is capable of being connected to the back module2.

The exoskeleton structure also comprises an attachment device 24allowing the back module 2 to be attached to the base module 1.

The attachment device 24 comprises a third part 241 mounted fixedly onthe base module 1 and a fourth part 242 mounted fixedly on the backmodule 2. More precisely, the third part 241 is attached to the belt 11.The fourth part 242 is attached to a lower end of the spinal columnsegment 21.

The fourth part 242 is capable of being attached to the third part 241,using screws for example, to attach the back module 2 to the base module1.

In addition, the third part 241 and the fourth part 242 comprise asocket and a plug capable of being plugged into the socket toelectrically connect the second battery 222 of the back module 2 to thecontrol unit 13 of the base module 1 when the fourth part 242 isattached to the third part 241.

Spinal Column Segment

FIG. 14 illustrates more precisely the spinal column segment 21. Thespinal column segment 21 comprises a plurality of vertebral elements 211stacked on top of each other.

The number of vertebral elements 211 can be adjusted depending on thesize of the user, which allows easy adaptation of the exoskeletonstructure to the morphology of the user.

Alternatively or as a complement, the backrest 22 can be mounted slidingalong the spinal column segment 21 so as to allow an adjustment of theback module 2.

The vertebral elements 211 can be formed from a rigid and lightmaterial, such as a composite material based on epoxy polymer filledwith carbon fibers for example.

The spinal column segment 21 also comprises one or more flexibleconnecting element(s) 212 allowing the vertebral elements 211 to beconnected to one another.

In the example illustrated in FIG. 14, each flexible connecting element212 extends inside the stack, passing through each of the vertebralelements 211. However, as a variant, the spinal column segment 21 couldcomprise a flexible connecting element in the form of a flexible tubularsheath encapsulating the vertebral elements 211.

In the example illustrated in FIG. 14, each flexible connecting element212 is an elongated element, such as a cable or an elastic cord.

Each flexible connecting element 212 has a first end connected to thecasing 221 of the backrest 22 and a second end connected to the fourthattachment part 242.

Each flexible connecting element 212 is held under tension inside thevertebral elements 211 so as to exert a longitudinal compression forceon the vertebral elements 211. The compression force has the effect ofholding the vertebral elements 211 squeezed against one another.

In this manner, the spinal column segment 21 has a stable equilibriumposition.

However, due to their elasticity, the flexible connecting elements 211allow deformation of the spinal column segment 21 during movements ofthe back of the user (flexure and/or radial rotation movements and/orlateral inclination of the back), while exerting on the vertebralelements 211 a return force tending to return the spinal column segment21 to its stable equilibrium position.

As illustrated in FIG. 15, each vertebral element 211 comprises a body213 having an arched shape, with a concavity oriented toward the bottomof the spinal column when the spinal column segment 21 extends along thespinal column of the user and the user is standing.

Each vertebral element 211 has a recess 214 and a protrusion 215, eachprotrusion 215 being capable of being received in a recess 214 ofanother vertebral element 211 situated immediately above or below in thestack.

Each vertebral element 211 if thus connected to the following vertebralelement by socketing a protrusion 215 into a recess 214. The recess 214and the protrusion 215 have shapes such that they allow a lateralinclination movement of the vertebral element 211 with respect to thefollowing one. Thus the recess 214 and the protrusion 215 form aconnection between two vertebral elements 211 allowing a lateralinclination of the trunk of the user.

Moreover, each vertebral element 211 has channels 221 and 223 providedinside the body 213 for the passage of flexible connecting elements 212and for the passage of electrical transmission cable(s) 224.

The back module 2 also comprises one or more electrical transmission ordata transmission cable(s) 224 extending inside the spinal columnsegment 21 through each of the vertebral elements 211, for connectingthe second battery 222 and actuators or sensors of the back module 2 tothe control unit 13 of the base module 1.

It should be noted that the electrical transmission cable(s) 224 have agreater length than the length of the spinal column segment 21 so thatthey allow deformation of the spinal column 21 without risking damagingthe cable(s).

The spinal column segment 21 allows both transmitting a vertical loadexerted on the back module 2 while allowing a certain freedom ofmovement of the spinal column of the user.

Elbow Module

As illustrated in FIGS. 1 to 5 and 13, each elbow module 4 comprises ahumeral portion 41 capable of being attached to the arm of the user, anelbow joint 42 and a radial portion 43 capable of being attached to theforearm of the user.

The humeral portion 41 comprises a humeral segment 411 capable ofextending along the arm of the user, and attachment straps 412 capableof surrounding the arm of the user to attach the humeral segment 411 tothe arm.

The radial portion 43 comprises a radial segment 431 capable ofextending along the forearm of the user and attachment straps 432capable of surrounding the forearm of the user to attach the radialsegment 431 to the forearm.

The radial portion 43 is connected to the humeral portion 41 through theelbow joint 42. The elbow joint 42 allows rotation of the radial portion43 with respect to the humeral portion 41 corresponding to a flexure orextension movement of the elbow of the user. The elbow joint 42 can alsocomprise an elbow actuator to assist the user during a flexure orextension movement of the elbow.

Shoulder Module

FIGS. 16 to 18 show schematically a shoulder module 3.

Each shoulder module 3 is capable of connecting an elbow module 4 to theback module 2.

The shoulder module 3 allows movement of the elbow module 4 with respectto the back module 2 according to three degrees of freedom, namely:

-   -   rotation of the elbow module 4 around a first axis parallel to        an abduction or adduction axis of the shoulder,    -   rotation of the elbow module around a second axis parallel to an        external or internal axis of rotation of the shoulder,    -   rotation of the elbow module around a third axis parallel to a        flexure or extension axis of the shoulder.

The shoulder module 3 comprises a first pivot 31, a four-bar mechanism32, a second pivot 33, a first connecting part 34 a third pivot 35, asecond connecting part 36, a fourth pivot 37, a third connecting part38, a fifth pivot 39, and a third connecting part 310.

The four-bar mechanism 32 comprises a first bar 321, a second bar 322, afirst joint 325 connecting the second bar 322 to the first bar 321, athird bar 323, a second joint 326 connecting the third bar 323 to thesecond bar 322, a fourth bar 324, a third joint 327 connecting thefourth bar 324 to the third bar 323 and a fourth joint 328 connectingthe fourth bar 324 to the first bar 321.

The four bars 321 to 324 are connected to one another by the four joints325 to 328 so as to form a deformable parallelogram in a plane parallelto the coronal plane of the user. The four-bar mechanism 32 alsocomprises an elastic element 329, extending along a diagonal of theparallelogram and connecting the first joint 325 to the third joint 327so as to create, on the four bars 321 to 324, a return force tending tooppose a deformation of the parallelogram due to the force of gravityexerted on the shoulder module 3. The elastic return element 329 is atension spring of which one of the ends is connected to the first joint325 and the other end is connected to the third joint 327.

The first bar 321 is mounted in rotation with respect to the casing 221of the backrest 22 by means of the first pivot connection 31, around asubstantially vertical axis.

Likewise, the third bar 323 is mounted in rotation with respect to thefirst connecting part 34 by means of the second pivot 33, around asubstantially vertical axis.

The second connecting part 36 is mounted in rotation with respect to thefirst connecting part 34 by means of the third pivot 35. The third pivot35 comprises an actuator.

The actuator comprises a stator and a rotor capable of being driven inrotation with respect to the stator around the first axis of rotation,the first axis of rotation being perpendicular to the axis of the secondpivot 33. The actuator allows assisting the user during an abduction oradduction movement of the shoulder. To this end, the first axis ofrotation X₁ is parallel to the axis of abduction or adduction of theshoulder.

The third connecting part 38 is connected to the second connecting part36 by means of the fourth pivot 37. The fourth pivot 37 allows rotationof the third connecting part 38 with respect to the second connectingpart 36 around a second axis of rotation X₂ corresponding to an externalor internal rotation movement of the arm of the user.

The fourth connecting part 310 is mounted in rotation with respect tothe third connecting part by means of the fifth pivot 39. The fifthpivot 39 allows rotation of the fourth connecting part 310 with respectto the third connecting part 38 around a third axis of rotation X₃. Thefifth pivot 39 comprises an actuator.

The actuator comprises a stator and a rotor capable of being driven inrotation with respect to the stator around the third axis of rotationX₃, the third axis of rotation X₃ being perpendicular to the axis of thefourth pivot 37. The actuator allows assisting the user during a flexureor extension movement of the shoulder. To this end, the third axis ofrotation X₃ is parallel to the axis of flexure and extension of theshoulder.

The first axis of rotation X₁ of the third pivot 35 intersects thesecond axis of rotation X₂ of the fourth pivot 37, perpendicular to it.Likewise, the third axis of rotation X₃ of the fifth pivot 39 intersectsthe second axis of rotation X₂ of the fourth pivot 37, perpendicular toit. However, the first axis of rotation X₁ and the third axis ofrotation X₃ intersect the second axis of rotation X₂ at distinct points.

When the arm of the user is at rest (that is when the arm extends alongthe body of the user in the standing position), the second axis ofrotation X₂ of the fourth pivot 37 is parallel to the axis of rotationof the second pivot 33. In addition, the third axis of rotation X₃ isperpendicular to the first axis of rotation X₁ of the third pivot 35,and to the second axis of rotation X₂ of the fourth pivot 37.

As illustrated in FIG. 17, the third connecting part 38 comprises twoparts 381 and 382 mounted sliding with respect to one another by meansof a first slideway 383. The sliding of the parts 381 and 382 withrespect to one another allows shortening or lengthening of the thirdconnecting part 38 during abduction or adduction movements of theshoulder of the user. The first slideway 383 comprises a first elasticreturn element 384 tending to oppose the separation of the parts 381 and382 with respect to one another, and therefore a lengthening of thethird connecting part 38. The first elastic return element 384 istherefore a tension spring.

As illustrated in FIG. 18, the fourth connecting part 310 comprises twoparts 3101 and 3102 mounted sliding one with respect to the other bymeans of a second slideway 3103. The sliding of parts 3101 and 3102 withrespect to one another allows shortening and lengthening of the fourthconnecting part 310 during rotation of the forearm of the user withrespect to the arm causing a flexure or an extension of the elbow. Thesecond slideway 3103 comprises a second elastic return element 3104tending to oppose the separation of the parts 3101 and 3102 with respectto one another, and therefore an extension of the fourth connecting part310. The second elastic return element 3104 is a tension spring.

As the axes of rotation X₁, X₂ and X₃ of the shoulder module 3 do notcoincide with the real axes of rotation of the joint complex of theshoulder of the user, the two slideways 383 and 3103 allow the length ofthe third connecting part 38 and the length of the fourth connectingpart 310 to vary so as to compensate the offset of the axes ofrevolution.

The fourth connecting part 310 is connected to the elbow joint 42 of theelbow module by means of an attachment device 10.

Device for Attaching the Shoulder Module to the Elbow Module

The exoskeleton structure comprises two attachment devices 10, eachattachment device 10 allowing attachment of a shoulder module 3 to anelbow module 4.

FIG. 19 shows schematically the attachment device 10. In the embodimentillustrated in this figure, the attachment device 10 is a so-called“bayonet type” attachment device, similar to the device 8 for attachingthe hip module 5 to the base module 1 illustrated in FIGS. 9, 10A and10B.

The attachment device 10 is capable of passing from an unlockedconfiguration in which the shoulder module 3 is detached from the elbowmodule 4, to a locked configuration in which the shoulder module 3 isattached to the elbow module 4.

The attachment device 10 comprises a first part 101 mounted fixedly onthe elbow module 4 and a second part 102 mounted movable in rotation onthe shoulder module 3.

More precisely, the first part 101 is attached to the stator of theactuator of the elbow joint 42. The second part 102 is mounted inrotation on the fourth connecting part 310 of the shoulder module 3around an axis X parallel to the direction of insertion of the secondpart 102 into the first part 101.

The second part 102 is capable of being snapped into the first part 101,so as to allow the reversible attachment of the shoulder module 3 to theelbow module 4.

The first part 101 and the second part 102 are identical to the firstpart 81 and the second part 82 of the device 8 for attaching the hipmodule 5 to the base module 1. The attachment device 10 also comprisesan elastic return element 103, in the form of a spring, capable ofloading the second part 102 in a direction opposite to the direction ofinsertion of the first part 102 into the first part 101.

Moreover, the first part 101 and the second part 102 each compriseelectrical contacts capable of electrically connecting the first battery12 and the control unit 13 of the base module 1 to the actuator of theelbow joint 42 when the second part 102 is in the locked configurationin the first part 101.

Backpack Support Module

As illustrated in FIGS. 20 and 21, the backpack support module 14comprises a hoop 141 and a support rod 142.

The hoop 141 is designed to be connected to the base module 1. The hoophas two opposite ends 143.

The backpack support module 14 also comprises two ball joints 145 andtwo attachment devices 16 allowing the hoop to be connected to the hipmodules 5.

In this manner, the weight of the backpack is transferred to the lowermodules, namely the hip modules 5, the knee modules 6 and the footmodules 7, which allows the user to lighten the load applied to theback.

The support rod 142 is designed to extend along the back of the user,parallel to the spinal column of the user. The rod 142 is capable ofbeing engaged in a pouch 171 of a backpack 17 to suspend the backpack 17from the backpack support module 14.

The rod 142 comprises a first rod element 1421, a second rod element1422 and a damper 1423.

The first rod element 1421 is connected to the hoop 141 by a pivot 144allowing rotation of the rod 142 with respect to the hoop 141 around anantero-posterior axis of the user. The pivot 144 allows the backpacksupport module to adapt to the movements of the hip of the user duringwalking or running.

The second rod element 1422 is capable of sliding with respect to thefirst rod element 1421 so as to vary a length of the rod 142.

The first rod element 1421 and the second rod element 1422 can be formedfrom a synthetic material (for example a composite material based onepoxy polymer) reinforced with carbon fibers. Moreover, the second rodelement 1422 can comprise an end portion formed from metal.

The second rod element 1422 can be telescoping, so as to allowadjustment of the length of the rod 142.

The damper 1423 is adapted to cushion the movement of the second rodelement 1422 with respect to the first rod element 1421 caused by thewalking of the user.

The damper 1423 thus allows a reduction in the jolts caused by movementsof the backpack 17 on the exoskeleton structure when the user walks,runs or jumps.

To this end, the damper 1423 comprises a cylinder 1424 attached to thefirst rod element 1421, a piston 1425 attached to the second rod element1422 and capable of sliding inside the cylinder 1424, and an elasticelement 1426 arranged between the first rod element 1421 and the secondrod element 1422.

The piston 1425 delimits in the interior of the cylinder 1424 twochambers, 1427 and 1428, containing a fluid, the sliding of the piston1425 inside the cylinder 1424 causing compression of the fluid containedin one of the chambers 1427, and transfer of the fluid to the otherchamber 1428.

The elastic element 1426 preferably has a stiffness greater than orequal to 2000 Newtons per meter. Such stiffness allows the eliminationof backpack oscillation amplification phenomena which could occur in theevent that the mass-spring system formed by the backpack 17 and theelastic element 1426 comes into resonance during walking or running ofthe user.

Moreover, the damper 1423 can have an adjustable damping ratio, whichallows the damping to be adapted to the mass of the backpack. In fact,the mass of the backpack can vary depending on the type of missioncarried out by the user. The adjustment of the damping ratio can beobtained by modifying the total volume of chambers 1427 and 1428 (bymeans of a screw, for example) so as to adjust a damping ratio of thedamper.

The backpack support module 14 also comprises a protective bellows seal1429 connecting the first rod element 1421 to the second rod element1422. The protective bellows seal 1429 allows a lengthening of the rod142 while still preventing the penetration of liquid or debris insidethe rod 142 and the damper 1423.

Moreover, the backpack support module 14 can comprises a force sensor toevaluate the mass of the bag 17 that is carried. The force sensor can bea compression strain-gage force sensor. The sensor can be disposed inthe lower portion of the rod 142 above the damper 1423.

Device for Attaching the Backpack Support Module to the Hip Module

FIG. 22 shows schematically an attachment device 16 allowing one end 143of the hoop 141 to be connected to the hip modules 5.

In the embodiment illustrated in this figure, the attachment device 16is a so-called “bayonet type” attachment device, similar to the device 8for attaching the hip module 5 to the base module 1, illustrated inFIGS. 9, 10A and 10B.

The attachment device 16 is capable of passing from an unlockedconfiguration in which the backpack module 14 is detached from the hipmodule 5, to a locked configuration in which the backpack module 14 isattached to the hip module 5.

The attachment device 16 comprises a first part 161 mounted fixedly onthe hip module 5, and a second part 162 mounted movable in rotation andin translation on the backpack support module 14.

More precisely, the first part 161 is attached to the stator 522 of theactuator 521 of the hip joint 52. The second part 102 is mounted inrotation on the hoop 141 by means of the ball joint 145. The second part162 is also mounted sliding with respect to the ball joint 145 along theaxis X.

The second part 162 is capable of being snapped into the first part 161,so as to reversibly attach the backpack support module 14 to the hipmodule 5 and consequently to the base module 1.

The first part 161 and the second part 162 are identical to the firstpart 81 and the second part 82 of the device 8 for attaching the hipmodule 5 to the base module 1. The attachment device 16 also comprisesan elastic return element 163, in the form of a spring, capable ofloading the second part 162 in one direction, opposite to the insertiondirection of the second part 162 into the first part 161.

In this manner, the hoop 141 is anchored at each of its ends 143 to thehip joints 52 of the hip modules 5. The weight of the backpack 17 isthus transferred to the ground by means of the lower modules, namely thehip modules 5, the knee modules 6 and the foot modules 7.

1. A modular exoskeleton structure for the transfer of forces and loadsapplied to an upper body portion of a user, the modular exoskeletonstructure comprising: a base module comprising a lumbar belt capable ofsurrounding a waist of the user, a first battery and a control unitattached to the lumbar belt, a back module configured to be attached tothe base module and a back of the user, the back module comprising asecond battery and a spinal column segment designed to extend along aspinal column of the user, the spinal column segment comprising aplurality of stacked vertebral elements exerting a return force tendingto return the spinal column segment to a stable equilibrium position inresponse to an application of a force or load, an upper moduleconfigured to be attached to the back module and upper extremities ofthe user, comprising: a bilateral shoulders module configured to belocated at shoulders of the user, comprising: a pair of jointsconfigured to be located at each of the shoulders of the user on thecoronal plan; a pair of joints configured to be located at each of theshoulders of the user on the sagittal plan; a proximal segmentconfigured to be located at a posterior part of the shoulders of theuser, the proximal segment being configured to be operatively connectedto the back module; and a distal segment configured to be located at alateral part of the shoulders of the user; a pair of arm modules eachcomprising: a proximal segment configured to be located at a forearm ofthe user; a distal segment configured to be located at an arm of theuser, the distal segment being operatively connected to the distalsegment of the bilateral shoulders module; and an elbow jointoperatively connecting the proximal segment to the distal segment; alower module configured to be attached to the base module and to belocated at lower extremities of the user, comprising: a hip moduleincluding a pair of hip joints each operatively connected to acorresponding femoral portion configured to be located at a respectivethigh of the user; a pair of knee modules each including a knee jointoperatively connecting a tibial portion configured to be located at acalf of the user and the proximal segment of the hip module; and a pairof foot modules each including an ankle joint operatively connecting afoot segment configured to be located at a foot of the user and thedistal segment of a corresponding knee module, and a ground contactelement; wherein in use the load applied to the upper body portion of auser is transferred to the lower body portion of the user and then tothe ground via the connections between the upper module, the base moduleand the lower module.
 2. The modular exoskeleton structure according toclaim 1, each of the hip joints includes a hip actuator comprising astator and a rotor capable of being driven in rotation with respect tothe stator to drive in rotation the corresponding proximal body segmentwith respect to the base module during a flexure or extension movementof a corresponding hip of the user, the corresponding proximal bodysegment being attached to the stator of the hip actuator.
 3. The modularexoskeleton structure according to claim 2, wherein the base module andthe hip module are operatively connected via a respective firstattachment part and a second attachment part forming a bayonet typeattachment device in which one of either the first attachment part or ofthe second attachment part comprises a radial pin, and the other of thefirst attachment part and the second attachment part comprises a curvedslot in which the radial pin can slide, the curved slot being curved insuch a manner that the sliding of the radial pin in the curved slot froman entrance of the curved slot to an end of the curved slot requires acombined translation and rotation movement of the second attachment partwith respect to the first attachment part, the translation beingaccomplished successively in a first direction, then in a seconddirection opposite to the first direction.
 4. The modular exoskeletonstructure according to claim 3, wherein the bayonet type attachmentdevice also comprises an elastic return element capable of urging thesecond attachment part in the second direction so as to hold the secondattachment part snapped into the first attachment part.
 5. The modularexoskeleton structure according to claim 4, wherein when the elasticreturn element urges the second attachment part in the second direction,the elastic return element tends to separate the second attachment partfrom the first attachment part.
 6. The modular exoskeleton structureaccording to claim 1, wherein the knee module comprises a connecting barcapable of being inserted into a femoral segment of the femoral portionto attach knee module to the hip module.
 7. The modular exoskeletonstructure according to claim 6, wherein the connecting bar is capable ofsliding inside the femoral segment of the hip module to allow adjustmentof a distance between the knee joint and the hip joint.
 8. The modularexoskeleton structure according to claim 1, wherein the foot modulefurther comprises a connecting bar capable of being inserted into atibial segment of the tibial portion to attach the foot module to theknee module.
 9. The modular exoskeleton structure according to claim 2,wherein the first attachment part and the second attachment part eachcomprise electrical contacts capable of electrically connecting thefirst battery and the control unit to the hip actuator when the secondattachment part is snapped into the first attachment part.
 10. Themodular exoskeleton structure according to claim 1, wherein theplurality of stacked vertebral elements are connected by a flexibleconnecting element so that the plurality of vertebral elements remain inthe stable equilibrium position and such that during a movement of theback of the user, the flexible connecting element allows a displacementof the stacked vertebral elements with respect to one another whilestill exerting a return force tending to return the spinal columnsegment to the stable equilibrium position.